1. Field of the Invention
The invention relates to a cuttings washer method for use in drilling and similar operations for a subterranean well.
2. Description of the Prior Art
During the drilling of a subterranean well, a drilling fluid or mud is circulated within the well bore to cool and lubricate the drilling bit and to remove drilling cuttings from the bottom of the well. At the well head, the cuttings are removed, and the drilling fluid is recirculated. When an oil base drilling fluid is used, however, residual oil clinging to the cuttings may contaminate the environment, such as the ocean or sea, or the like. To avoid such contamination, and, in some situations, to comply with some government regulations, it is therefore desirable to wash such drilling cuttings before disposing of them, particularly from an offshore drilling rig.
Equipment for washing cuttings is commercially available. In known systems, cuttings are deposited in a tub containing a wash solution and are agitated therein. The cuttings are then deposited on a horizontal vibrating screen. Wash solution and oil contaminants are shaken off the cuttings particles and through the screen. The vibratory motions impel the cuttings particles off the edge of the screen into the ocean or other suitable depositary.
Depositing the cuttings in a washing tub, removing them after agitation, and depositing them on a shaker is relatively time consuming, hence in some drilling and related operations, even two of such systems operating at the same time have been unable to keep up with the drilling rate.